1. Field of the Invention
The described technology relates generally to an organic light emitting diode (OLED) display. More particularly, the described technology relates generally to an OLED display of which light extraction efficiency is improved.
2. Description of the Related Art
An organic light emitting diode (OLED) display is a self emissive display device that is displays images with organic light emitting diodes. The organic light emitting diode display differs from a liquid crystal display (LCD) in that it does not require a separate light source, and has a relatively small thickness and weight. Furthermore, as the organic light emitting diode display involves high quality characteristics such as low power consumption, high luminance, and short response time, it is spotlighted as a next generation display device for portable electronic appliances.
Usually, one or more electrodes of the organic light emitting diodes in the organic light emitting diode display, and other various metal wires thereof, reflect external light that is incident thereto from the outside. Accordingly, when the organic light emitting diode display is used in bright areas, the black color expression and the contrast thereof become poor due to the reflection of external light.
In order to solve such a problem, polarizing and phase retardation plates are provided on the organic light emitting diode so as to suppress the reflection of external light. However, with the conventional method of suppressing the reflection of external light based on the polarizing and phase retardation plates, it is problematic that much light generated from an organic emissive layer is eliminated when the external light is discharged to the outside through the polarizing and phase retardation plates.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.